1. Field of the Invention
This invention relates to novel chemical compounds and to their use as photographic silver halide developing agents.
2. Description of the Prior Art
A variety of reductone compounds including amino reductones are known, and a number of such compounds have been used as reagents in photography. For example, U.S. Pat. No. 3,690,872 is directed to the use of certain amino hydroxy cycloalkenones as silver halide developing agents including 3-amino-2-hydroxy-2-cyclopentenones and 3-amino-2-hydroxy-2-cyclohexenones substituted in the 4-position with alkyl containing 1 to 5 carbon atoms. As discussed in this patent at column 3, lines 14-75, the preparation of 2-hydroxy-3-morpholino-2-cyclohexenone is typical of the method of preparing the amino hydroxy cycloalkenone developing agents and comprises refluxing equimolar amounts of morpholine, 3-chloro-1,2-cyclohexanedione and triethylamine in anhydrous ethyl acetate under at atmosphere of nitrogen. U.S. Pat. No. 3,700,442 is directed to the use of esters of amino reductones, e.g., esters of amino hexose reductones as developing agent precursors. As discussed in this patent at column 3, lines 13-24, a typical method of preparing the described amino hexose reductones consists of heating a reducing sugar and an aliphatic or cyclic secondary amine in a substantially water free reaction medium in the presence of an acidic reductone-forming catalytic agent such as phosphoric acid.
The present invention is concerned with a new class of amino hydroxy reductones which also are useful as silver halide developing agents.